The invention relates to a process for the production of largely amorphous polyalphaolefins and the polymer obtained therefrom, which are characterized by a softening point (measured by the ring and ball method corresponding to DIN 52 011) between 70.degree. and 140.degree. C., a melt viscosity (at 190.degree. C.) between 1,000 and 100,000 mPas (determined by the methods described in ASTM D 3236), a density less than 0.90 g/cm.sup.3, a needle penetration (determined by the methods described in DIN 52 010) of 5 to 50 0.1 mm and a molecular inhomogeneity, U=Mw/Mn-1 (determined by gel permeation chromatography), of at most 6.
Reaction systems, consisting of reacting a polyolefin and a radical donor are known. Homopolymers and copolymers of ethene can be crosslinked in the presence of radical donors with energy input. According to the rise in the molecular weight, elastomeric, i.e., rubber-like, products with improved dimensional stability at higher temperatures or improved chemical resistance are obtained.
In addition, homopolymers based on propene can be mechanically/thermally or radically decreased in molecular weight. The end products, in comparison with the starting polymers, have a higher melt flow index and, according to experience, a narrower molecular weight distribution. The latter process step has gained particular importance for the production of fiber material.
In the case of amorphous or largely amorphous polyalphaolefins, comparable process steps have not been taken in practice, since a practical use could not be seen. At most, an exception in some respect is made in the case of atactic polypropylene (APP) occurring during the production of isotactic polypropylene where high molecular weight APP must be subjected to a decomposition step to be able to be marketed at all. The starting product in such cases has a softening point (ring and ball method) of over 150.degree. C. as well as a melt viscosity (at 190.degree. C.) of over 200,000 mPas, often even far over 500,000 mPas. The decomposition step usually leads to products with melt viscosities (at 190.degree. C.) between 50,000 and 200,000 mPas, which have few noncritical uses such as, for example, bitumen modification.
Because of this experience with polyolefins, it would be expected that decomposition and crosslinking occur as competing reactions in polyolefins, which are not synthesized exclusively from propene, such as, for example, ethene/propene/1-butene terpolymers. Therefore, no appreciable lowering of the molecular weight or narrowing of the molecular weight distribution are expected to occur.